Poor Habitat Quality Research Articles

Biogeographical factors affecting the distribution of stream salamanders on the Cumberland Plateau, USA

Geophysical and climate conditions play an important role in the distribution of organisms at both fine and broad scales. Headwater streams integrate changes at broad geographical scales and serve as important regions of nutrient processing and support high biodiversity. Stream salamanders are important members of headwater aquatic communities as both predators and prey. Combined with their biphasic life histories and physiological requirements, stream amphibians may serve as indicators for headwater stream conditions. We surveyed 50 streams for salamander occupancy, across eight counties of the southern Cumberland Plateau in Tennessee for which we are unaware of any stream amphibian distribution data. Our objective was to determine what variables best-predicted stream amphibian occupancy among species with variable life histories and habitat needs. Models were generated to determine the effects of elevation, catchment forest cover, and total catchment size as indicators of stream condition. We found species showed no significant responses to forest cover. Though forest cover has previously been the primary predictor of stream amphibian occupancy in streams across the United States, stream amphibian occupancy of the southern Cumberland Plateau was most closely associated with elevation and catchment size. Thus, the unique topography of the southern Cumberland Plateau may instead be the more important factor driving occupancy patterns. Despite limited evidence in this study for negative human impacts on salamander occupancy, low occupancy and abundance relative to other ecoregions suggests either poor quality habitat or large historic impacts. Developing a more comprehensive understanding of regional stream salamander occupancy patterns is necessary to ensure effective management and habitat conservation in a region with limited description of stream ecology.

Floaters may buffer the extinction risk of small populations: an empirical assessment.

The high extinction risk of small populations is commonly explained by reductions in fecundity and breeder survival associated with demographic and environmental stochasticity. However, ecological theory suggests that population extinctions may also arise from reductions in the number of floaters able to replace the lost breeders. This can be particularly plausible under harsh fragmentation scenarios, where species must survive as small populations subjected to severe effects of stochasticity. Using a woodpecker study in fragmented habitats (2004-2016), we provide here empirical support for the largely neglected hypothesis that floaters buffer population extirpation risks. After controlling for population size, patch size and the intrinsic quality of habitat, populations in patches with floaters had a lower extinction probability than populations in patches without floaters (0.013 versus 0.131). Floaters, which often replace the lost breeders, were less likely to occur in small and low-quality patches, showing that population extirpations may arise from unnoticed reductions in floater numbers in poor-quality habitats. We argue that adequate pools of the typically overlooked floaters may buffer extirpation risks by reducing the detrimental impacts of demographic and environmental stochasticity. However, unravelling the influence of floaters in buffering stochastic effects and promoting population stability require additional studies in an ample array of species and stochastic scenarios.

The Emergent Properties of Conspecific Attraction Can Limit a Species' Ability to Track Environmental Change.

Multiple biotic, abiotic, and evolutionary constraints interact to determine a species' range. However, most species are not present in all suitable and accessible locations. Dispersal ability may explain why many species do not occupy all suitable habitat, but highly mobile species also exhibit a mismatch. Habitat selection behavior where individuals are site faithful and settle near conspecifics could create a social pressure that make a species' geographic range resistant to change. We investigated this possibility by using an individual-based model of habitat selection where habitat quality moved each year. Our model demonstrated the benefits of conspecific attraction in relatively stable environments and its detrimental influence when habitat quality shifted rapidly. These results were most apparent when adult survival was high, because site fidelity led to more individuals occupying poor-quality habitat areas as habitat quality changed. These individuals attracted other dispersing individuals, thereby decreasing the ability to track shifts in habitat quality, which we refer to as "social inertia." Consequently, social inertia may arise for species that exhibit site fidelity and conspecific attraction, which may have conservation implications in light of climate change and widespread alteration of natural habitats.

Source-Sink Dynamics: a Neglected Problem for Landscape-Scale Biodiversity Conservation in the Tropics

Ecologists have long recognised that populations can persist in poor-quality habitats with below-replacement population growth rates (‘sinks’) provided there is continual immigration from areas with positive intrinsic growth (‘sources’). Source-sink dynamics complicate the assessment of species-environment relationships, because species’ presence or density can be poorly correlated with underlying population productivity. Yet, applied conservation research often uses presence or abundance data to assess species responses to environmental change, particularly in the tropics where few long-term ecological studies are established. This approach assumes that abundance data reliably indicate habitat quality, but in sinks, this assumption can be violated. We review the recent literature and identify a regional bias in reporting of source-sink phenomena, with 71% of the 210 studies considered coming from temperate regions, particularly Eurasia and North America. Very few studies come from tropical and subtropical biomes, where human-driven biodiversity loss is occurring most rapidly, with over 80% not providing strong evidence in the form of demographic, dispersal or molecular data. Source-sink studies in tropical regions have predominantly investigated populations exposed to hunting/exploitation, with few examining land-use change. We review policy-relevant arenas where better treatment of source-sink dynamics is a priority: spatial conservation planning, assessments of land-sparing versus land-sharing, the conservation value of selectively logged forests, and species distribution modelling. Finally, we discuss ways to improve understanding of source-sink dynamics, particularly in tropical regions. Failure to detect source-sink patterns across the hyperdiverse tropics could limit the efficacy of conservation practice, leading us to underestimate the severity of human impacts on biodiversity.

An approach for identifying cryptic barriers to gene flow that limit species' geographic ranges.

Species' geographic range limits are most often not demarcated by obvious dispersal barriers. Poor-quality habitat at the edge of a species' range can prevent range expansion by preventing outward migration or through reducing adaptive potential resulting from decreased genetic diversity. We identified habitat variables that constrain gene flow across the entire geographic range of an endemic salamander (Ambystoma barbouri) in the eastern United States, and we tested whether increased resistance resulting from these variables provides cryptic dispersal barriers at the range edges. Using polymorphic microsatellite loci, we first identified three genetic clusters that are separated by the Ohio and Kentucky rivers. Through a combination of landscape genetic analyses and generalized dissimilarity modelling, we then classified variables that (i) restrict gene flow in each of the genetic clusters across the geographic distribution of A.barbouri and (ii) become more common towards the peripheries of the distribution. A decrease in limestone availability and an increase in growing season precipitation were correlated with high resistance to gene flow across the range, and both became more common at the edges of the species' distribution. However, other landscape variables were more important for explaining variation in geneflow rates in different portions of the range, such as increased mean annual temperature and frost-free period in the south vs. growing season precipitation in the north. Taken together, these results suggest that there are both range-wide and regionally specific cryptic habitat barriers preventing geographic range expansion. Species 'geographic range limits are probably governed by a set of ecological and evolutionary factors, and our landscape genetic approach could be applied to gain additional insight into many systems.

Experimental demonstration of an ecological trap for a wild bird in a human-transformed environment

An ecological trap occurs when animals prefer to settle in poor-quality habitats even though alternative high-quality habitats are available. Thus, to find evidence of a trap one must show (1) a habitat preference and (2) a mismatch between the settlement decision and reproduction or survival. However, demonstrations of traps in the wild are currently limited because the misleading cues have to be identified and are usually difficult to manipulate experimentally. Places where humans transform habitats, such as urbanized areas, are particularly prone to this ecological phenomenon. Here we tested whether the size of a human-made structure (artificial cavities) can induce maladaptive breeding responses via an ecological trap mechanism in an urban secondary-cavity nesting bird, the great tit, Parus major. Previous studies showed that great tits prefer to breed in large cavities; cavity size is thus used as a cue in nest site selection. Reproductive investment in great tits has also been shown to be influenced by the breeding cavity size. However, this behaviour can only be adaptive if cavity size matches the quality of the breeding habitat. This is not necessarily the case in urbanized environments where natural habitat has been removed or breeding habitat modified. We performed a cavity choice experiment, providing an opportunity for great tits to choose between three cavity size options, and monitored their subsequent breeding attempts. We found that urban great tits preferred the largest artificial cavities for breeding when they could choose between small, medium-sized and large cavities. Individuals from the largest cavities also invested more in egg production, yet had a lower fledging success than those from medium-sized cavities, experimentally showing a trap mechanism in free-living animals. With this study, we shed light on maladaptation associated with human-transformed habitat.

Weighing the relative potential impacts of climate change and land-use change on an endangered bird.

Climate change and land‐use change are projected to be the two greatest drivers of biodiversity loss over the coming century. Land‐use change has resulted in extensive habitat loss for many species. Likewise, climate change has affected many species resulting in range shifts, changes in phenology, and altered interactions. We used a spatially explicit, individual‐based model to explore the effects of land‐use change and climate change on a population of the endangered Red‐cockaded Woodpecker (RCW; Picoides borealis). We modeled the effects of land‐use change using multiple scenarios representing different spatial arrangements of new training areas for troops across Fort Benning. We used projected climate‐driven changes in habitat and changes in reproductive output to explore the potential effects of climate change. We summarized potential changes in habitat based on the output of the dynamic vegetation model LPJ‐GUESS, run for multiple climate change scenarios through the year 2100. We projected potential changes in reproduction based on an empirical relationship between spring precipitation and the mean number of successful fledglings produced per nest attempt. As modeled in our study, climate change had virtually no effect on the RCW population. Conversely, simulated effects of land‐use change resulted in the loss of up to 28 breeding pairs by 2100. However, the simulated impacts of development depended on where the development occurred and could be completely avoided if the new training areas were placed in poor‐quality habitat. Our results demonstrate the flexibility inherent in many systems that allows seemingly incompatible human land uses, such as development, and conservation actions to exist side by side.

Nest site selection and nutritional provision through excreta: a form of parental care in a tropical endogeic earthworm.

Nest construction is a common form of parental care in soil organisms. However, it is unknown whether the tropical earthworm Pontoscolex corethrurus produces nests in soils with low nutritional quality habitats. Here we studied the reproductive behaviour and nest site selection of P. corethrurus, and tested the hypothesis whether P. corethrurus produces more cocoons in habitats with low nutritional quality. In bidimensional terrariums we evaluated the combined effect of the nutritional quality of habitat: (Poor Quality Habitat = PQH, Medium Quality Habitat = MQH, High Quality Habitat = HQH) and soil depth (Shallow, Intermediate, Deep) in a factorial 32 design. The number and biomass of cocoons, progeny and the production of internal and external excreta were evaluated. The quality habitat and depth of soil and their interaction had a significant effect on nest site construction and the deposition of internal excreta. Pontoscolex corethrurus built a higher amount of nests in the PQH-Intermediate and MQH-Intermediate treatments while more internal excreta were found in the HQH-Intermediate treatment. Offspring biomass was positively associated with internal excreta in the PQH (soil only) and MQH (soil + grass) treatments, suggesting that this could be a form of parental care. Since P. corethrurus produces more cocoons in low and medium quality habitats, while produces more internal excreta at high quality habitats, there does not seem to be an association between number of offspring and parental care. We suggest P. corethrurus could have two reproductive strategies that act as diversified bet-hedging (do not put all cocoons in one basket) behavior in unpredictable environment, and thus build a higher amount of nests in low and medium quality habitats; and another where they produce more internal excreta as a form of parental care in high quality habitats. Parental care in the form of internal excreta may be particularly important in poor and medium quality habitats where offspring biomass increased with internal excreta. Further research is needed on the ecological conditions that favour the evolution of parental care in earthworms according to their ecological category (epigeic, endogeic and anecic).

Behuria mestrealvarensis (Melastomataceae): a new species on an inselberg in Espírito Santo, Brazil

Behuria mestrealvarensis (Melastomataceae) from the state of Espírito Santo, Brazil, is described, illustrated and compared with B. capixaba, the species most similar to it. Behuria mestrealvarensis differs from B. capixaba by the glabrous petioles and hypanthia, by the solitary flowers or these in simple or compound triads up to 7 flowers, elliptic bracteoles almost the same size of the pedicel and hypanthium, sepals with eciliate margins and ovary apex with trichomes up to 0.5 mm. It occurs in a single locality, on an isolated, ca. 800m elev. inselberg. Due to its restricted occupancy area, fragmented landscape and poor habitat quality, this species must be considered as Critically Endangered according to IUCN criteria.

Spatial organization and intraspecific relationships of the southern water vole (Arvicola sapidus) in a Mediterranean mountain river: what is the role of habitat quality?

An understanding of population dynamics, especially in endangered species that present metapopulation structures, such Arvicola sapidus, is important to gain knowledge of the dispersal and patterns of both occupation and space use. Here, we use radio tracking to report for the first time the relationship of the southern water vole with the environment in a Mediterranean mountain riparian area and also the relationships between individuals. Along the Montsant River, the size of the home ranges, the average distance travelled daily, the population density and the habitat quality were contrasted. In the subsection with better quality habitat, both the home ranges and distances travelled were smaller than in the subsection with poorer quality habitat, whilst population density was higher in the subsection with better quality habitat. Interactions (static and dynamic) between individuals reflected low sociality, especially between members of different groups. Within a group, adult males did not interact, but interactions between male and female adults intensified during the reproductive period. The home ranges of individuals changed with the emergence of new available gaps and in response to reproduction needs. Tracking a dispersant young male showed a trajectory in stages and made obvious the high risk of predation during this period. Our results here, and previously, indicate the possible effect of habitat quality on space use and relationships between individuals, emphasising the importance of the quality and structure of habitat in the conservation of the southern water vole.

Environmental and genetic determinants of innovativeness in a natural population of birds.

Much of the evidence for the idea that individuals differ in their propensity to innovate and solve new problems has come from studies on captive primates. Increasingly, behavioural ecologists are studying innovativeness in wild populations, and uncovering links with functional behaviour and fitness-related traits. The relative importance of genetic and environmental factors in driving this variation, however, remains unknown. Here, we present the results of the first large-scale study to examine a range of causal factors underlying innovative problem-solving performance (PSP) among 831 great tits (Parus major) temporarily taken into captivity. Analyses show that PSP in this population: (i) was linked to a variety of individual factors, including age, personality and natal origin (immigrant or local-born); (ii) was influenced by natal environment, because individuals had a lower PSP when born in poor-quality habitat, or where local population density was high, leading to cohort effects. Links with many of the individual and environmental factors were present only in some years. In addition, PSP (iii) had little or no measurable heritability, as estimated by a Bayesian animal model; and (iv) was not influenced by maternal effects. Despite previous reports of links between PSP and a range of functional traits in this population, the analyses here suggest that innovativeness had weak if any evolutionary potential. Instead most individual variation was caused by phenotypic plasticity driven by links with other behavioural traits and by environmentally mediated developmental stress. Heritability estimates are population, time and context specific, however, and more studies are needed to determine the generality of these effects. Our results shed light on the causes of innovativeness within populations, and add to the debate on the relative importance of genetic and environmental factors in driving phenotypic variation within populations.

Context-dependent outcomes in a reproductive mutualism between two freshwater fish species.

The development of encompassing general models of ecology is precluded by underrepresentation of certain taxa and systems. Models predicting context-dependent outcomes of biotic interactions have been tested using plants and bacteria, but their applicability to higher taxa is largely unknown.We examined context dependency in a reproductive mutualism between two stream fish species: mound nest-building bluehead chub Nocomis leptocephalus and mountain redbelly dace Chrosomus oreas, which often uses N.leptocephalus nests for spawning. We hypothesized that increased predator density and decreased substrate availability would increase the propensity of C.oreas to associate with N.leptocephalus and decrease reproductive success of both species.In a large-scale insitu experiment, we manipulated egg predator density and presence of both symbionts (biotic context), and replicated the experiment in habitats containing high- and low-quality spawning substrate (abiotic context).Contradictory to our first hypothesis, we observed that C.oreas did not spawn without its host. The interaction outcome switched from commensalistic to mutualistic with changing abiotic and biotic contexts, although the net outcome was mutualistic.The results of this study yielded novel insight into how context dependency operates in vertebrate mutualisms. Although the dilution effect provided by C.oreas positively influenced reproductive success of N.leptocephalus, it was not enough to overcome both egg predation and poor spawning habitat quality. Outcomes of the interaction may be ultimately determined by associate density. Studies of context dependency in vertebrate systems require detailed knowledge of species life-history traits.

Comparative test of ecological assessment methods of lowland streams based on long-term monitoring data of macrophytes

Ecological assessment of water courses is required by the European Water Framework Directive (WFD). Assessment by means of macrophytes is impeded by insufficient knowledge on the relations between assessment scores and the dynamics of environmental parameters. Data from a long-term observation of macrophyte dynamics over 21years in two lowland rivers were used for testing the performance of six widely used assessment methods. Six sample sites situated in two lowland streams were selected. Four sites were classified as of moderate habitat quality and two sites as of poor habitat quality in the context of WFD. Assessment methods generally showed a poor performance in recognizing the ecological status of the annual observations. Status was more often over- than underestimated. Performance of methods differed among individual rivers and among river zones. Assessment scores mostly showed a steady decline, even though all sites obviously remained in the same habitat quality class throughout the observation period. Variation of most environmental factors was largely unrelated to assessment scores. Fluctuations of assessment scores were partly related to single natural disturbance events such as high discharge. Increased shading by marginal trees was reflected negatively by most assessment scores. Assessment scores were highly correlated with species richness and total abundance. The best overall performance was shown by the North-Rhine Westphalian (NRW) method. In contrast to single metric methods it can be adapted to individual properties of a reach in a flexible way. Macrophyte assessment based on the pressure-impact framework did not lead to a satisfying result in our case study. Improvement of species assessment scores and inclusion of functional properties such as growth form may help to overcome the present difficulties.

Fish embryos on land: terrestrial embryo deposition lowers oxygen uptake without altering growth or survival in the amphibious fish Kryptolebias marmoratus.

Few teleost fishes incubate embryos out of water, but the oxygen-rich terrestrial environment could provide advantages for early growth and development. We tested the hypothesis that embryonic oxygen uptake is limited in aquatic environments relative to air using the self-fertilizing amphibious mangrove rivulus, Kryptolebias marmoratus, which typically inhabits hypoxic, water-filled crab burrows. We found that adult mangrove rivulus released twice as many embryos in terrestrial versus aquatic environments and that air-reared embryos had accelerated developmental rates. Surprisingly, air-reared embryos consumed 44% less oxygen and possessed larger yolk reserves, but attained the same mass, length and chorion thickness. Water-reared embryos moved their opercula ∼2.5 more times per minute compared with air-reared embryos at 7 days post-release, which probably contributed to the higher rates of oxygen uptake and yolk utilization we observed. Genetically identical air- and water-reared embryos from the same parent were raised to maturity, but the embryonic environment did not affect growth, reproduction or emersion ability in adults. Therefore, although aspects of early development were plastic, these early differences were not sustained into adulthood. Kryptolebias marmoratus embryos hatched out of water when exposed to aerial hypoxia. We conclude that exposure to a terrestrial environment reduces the energetic costs of development partly by reducing the necessity of embryonic movements to dispel stagnant boundary layers. Terrestrial incubation of young would be especially beneficial to amphibious fishes that occupy aquatic habitats of poor water quality, assuming low terrestrial predation and desiccation risks.

Population size is weakly related to quantitative genetic variation and trait differentiation in a stream fish.

How population size influences quantitative genetic variation and differentiation among natural, fragmented populations remains unresolved. Small, isolated populations might occupy poor quality habitats and lose genetic variation more rapidly due to genetic drift than large populations. Genetic drift might furthermore overcome selection as population size decreases. Collectively, this might result in directional changes in additive genetic variation (VA ) and trait differentiation (QST ) from small to large population size. Alternatively, small populations might exhibit larger variation in VA and QST if habitat fragmentation increases variability in habitat types. We explored these alternatives by investigating VA and QST using nine fragmented populations of brook trout varying 50-fold in census size N (179-8416) and 10-fold in effective number of breeders, Nb (18-135). Across 15 traits, no evidence was found for consistent differences in VA and QST with population size and almost no evidence for increased variability of VA or QST estimates at small population size. This suggests that (i) small populations of some species may retain adaptive potential according to commonly adopted quantitative genetic measures and (ii) populations of varying sizes experience a variety of environmental conditions in nature, however extremely large studies are likely required before any firm conclusions can be made.

Who escapes detection? Quantifying the causes and consequences of sampling biases in a long-term field study.

Inferences drawn from long-term field studies are vulnerable to biases in observability of different classes of individuals, which may lead to biases in the estimates of selection, or fitness. Population surveys that monitor breeding individuals can introduce such biases by not identifying individuals that fail early in their reproductive attempts. Here, we quantify how the standard protocol for detecting breeding females introduces bias in a long-term population study of the great tit, Parus major. We do so by identifying females whose breeding attempts fail before they would normally be censused and explore whether this early failure can be predicted by a number of intrinsic and extrinsic factors. We investigate the effect of these biases on estimates of reproductive performance and selection. We show that females that go undetected by standard censusing because they fail early in their breeding attempt were less likely to have been previously trapped within our study site and were more likely to breed in poor-quality habitats. Furthermore, we demonstrate that this bias sampling had lead previous studies on this population to overestimate the reproductive performance of unringed females, which are likely to be immigrants to the population. Finally, we show that these biases in detectability influence estimates of selection on a key life-history trait. While these conclusions are specific to this study, we suggest that such effects are likely to be widespread and that more attention should be given to whether or not methods for surveying natural populations introduce systematic bias that will influence conclusions about ecological and evolutionary processes.

Small mammals in farmlands of Argentina: Responses to organic and conventional farming

Despite the important positive role that small mammals have in agricultural systems, mainly through their contribution to food webs, few studies have been conducted on the biodiversity and abundance of this group. Considering that Argentina is one of the most important agricultural regions of the world, our objective was to assess the effect of farming practices (organic vs. conventional) on species richness and abundance of small mammals in border habitats from agroecosystems of central Argentina. We predicted that the effects of farming practices on small mammal populations would vary with the degree of habitat specialization of species. We expected higher species richness and abundance of specialist species in border habitats of organic than on conventional farms. We found that farming practices did not explain species richness; the number of species in border habitats was low with small variation between managements. Management, season and vegetation volume explained abundance of both specialist and generalist species in border habitats, but with additive effects in the former and interactive effects in the latter. During summer, Calomys musculinus, Calomys laucha and Akodon azarae were more abundant in border habitats of organic than on conventional farms. This could be related to the highest reproductive activity of these species in this season, associated to the highest habitat quality of organic border habitats. Also, organic farms may have an important role for specialist species in poor-quality habitats at the beginning and at the end of the reproductive period (spring and autumn). Our results showed a positive trend in small mammal abundance of organic farms in farmlands under intensive agriculture. The differences between Argentinian and European agriculture systems are discussed.

Habitat Characteristics within a Zone of Separation Between the Ranges of Two Species of Pocket Gophers

Abstract Gaps between distributions of closely related species have been noted in the literature but little empirical research exists to explain these patterns. One hypothesis is poor habitat quality occurs within the gaps and therefore prevents species from inhabiting these areas. Multiple examples of gaps between species distributions can be found among different species of pocket gophers. The objective of this research was to analyze a zone of separation between Geomys bursarius and Cratogeomys castanops in southwest Kansas. Habitat suitability maps were produced using Maxent (3.3.2) for each species throughout the study area. Values of habitat suitability and important habitat variables were compared between locations within the zone of separation and presence localities. The most important variable for predicting habitat suitability for G. bursarius was percent sand, while both percent sand and clay were important for C. castanops. Habitats within the zone of separation were significantly less suitab...

Critical steps to ensure the successful reintroduction of the Eurasian red squirrel

Wildlife reintroduction strategies aim to establish viable long–term populations, promote conservation awareness and provide economic benefits for local communities. In Portugal, the Eurasian red squirrel (Sciurus vulgaris) became extinct in the 16th century and was reintroduced in urban parks in the 1990s, mainly for aesthetic and leisure purposes. We evaluated the success of this reintroduction in two urban parks and here described the critical steps. We assessed habitat use, population density and abundance, and management steps carried out during reintroduction projects. Reintroductions have been successful to some extent given squirrels are present 20 years after release. However, populations in both parks are declining due to the lack of active management and poor quality habitat. Successful reintroduction of Eurasian red squirrel in areas without competition of alien tree squirrels involves three critical main stages. The pre–project stage includes studies on habitat quality, genetic proximity between donors and closest wild population, and health of donor stocks. In the release stage, the number of individuals released will depend on resource variability, and the hard release technique is an effective and economically viable method. Post–release activities should evaluate adaptation, mitigate mortality, monitor the need for supplementary feeding, provide veterinary support, and promote public awareness and education.

Annual variation in long‐distance dispersal driven by breeding and non‐breeding season climatic conditions in a migratory bird

Long‐distance dispersal is a fundamental process in ecology and evolution but the factors that influence these movements remain poorly understood in most species. We used stable hydrogen isotopes to quantify the rate and direction of long‐distance immigration in a breeding population of American redstarts and to test whether the settlement decisions that result in long‐distance dispersal are driven by habitat saturation or by the phenology of breeding‐season resources. Our results provide evidence that both natal dispersal and breeding dispersal were influenced by the timing of breeding‐season phenology, with both age classes more likely to disperse north in years when the onset of breeding‐season phenology occurs earlier than normal. Yearlings were also more likely to disperse north following winters with poor habitat quality on their non‐breeding grounds, demonstrating that carry‐over effects from the non‐breeding season influence natal dispersal in this species. Collectively, these results are consistent with the hypothesis that American redstarts use the phenology of breeding season resources as a cue to select breeding sites. Our results suggest that long‐distance dispersal may allow individuals to rapidly respond to advancing phenology caused by global climate change, though their ability to do so may be constrained by long‐term decline in habitat quality predicted for their tropical non‐breeding grounds.